From the air it looks like a huge lake, fed by many tributaries, but on the ground it turns out to be a murky expanse of water, in which no fish or algae can survive. The shore is coated with a black crust, so thick you can walk on it. Into this huge, 10 sq km tailings pond nearby factories discharge water loaded with chemicals used to process the 17 most sought after minerals in the world, collectively known as rare earths.
The town of Baotou, in Inner Mongolia, is the largest Chinese source of these strategic elements, essential to advanced technology, from smartphones to GPS receivers, but also to wind farms and, above all, electric cars. The minerals are mined at Bayan Obo, 120km farther north, then brought to Baotou for processing.
The concentration of rare earths in the ore is very low, so they must be separated and purified, using hydro-metallurgical techniques and acid baths. China accounts for 97% of global output of these precious substances, with two-thirds produced in Baotou.
The foul waters of the tailings pond contain all sorts of toxic chemicals, but also radioactive elements such as thorium which, if ingested, cause cancers of the pancreas and lungs, and leukaemia. “Before the factories were built, there were just fields here as far as the eye can see. In the place of this radioactive sludge, there were watermelons, aubergines and tomatoes,” says Li Guirong with a sigh.